Kahn, who recently directed the actioner Torque, carefully storyboarded two days of stunts to capture kinetic in-camera action. "It's really not as exciting as it looks when shooting," he insists. "It's very mechanical, very disciplined. If you're doing everything right it shouldn't be that thrilling-otherwise people's lives are at risk." Nonetheless, extreme footage of cars travelling 90mph, then spinning 360 degrees, created the necessary template for Kroma to seamlessly combine CG effects with Kahn's live action. Two more days of greenscreen ensued, placing each driver in a rig to simulate the movement within a race car.
Kroma used Softimage XSI for all 3-D modeling, while Avid DS took care of 2-D, compositing and finishing. Kroma visual effects supervisor/compositor Bert Yukich worked closely with Kahn during the shoot and post process, carefully adding exterior views of the racetrack to the greenscreen footage. Touches such as the addition of CG visors reflecting the movement of the track help sell the effect. "The interior of each vehicle was completely built from scratch-any time you transition from outside to inside the car, it's all CG," explains Yukich, who added CG safety gear and other car enhancements inside the chassis of each vehicle.
"Rear Ended" also features a stadium filled with CG racing fans. "We made clusters of people a hundred at a time, replicated them, then added specific movement," says Yukich.